Microphotography optical system

Abstract

The utility model discloses a macro photography optical system, and particularly relates to the field of optical imaging, and the macro photography optical system comprises a bonding lens, a focusing group lens, a rear focusing lens group and an image plane lens which are sequentially arranged from the object side to the image side along the optical axis direction. According to the invention, the spherical lens made of a full-glass material is adopted, the variable aperture is arranged between the focusing groups and moves along with the focusing groups, the aberration level at each focusing distance is improved and balanced, and the combined balsaming lens has an aberration eliminating function and is fixed relative to an imaging surface; dust, water vapor and the like are prevented from entering the lens when the focusing group moves, the last lens of the lens group is arranged to be a convex lens, the effects of reducing the main light incident angle of each view field and increasing the back focal length are finally achieved, the lens group is suitable for a single lens reflex camera, a micro single camera and even a film camera, and a good imaging effect is achieved.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and more specifically, to a macro photography optical system. Background Art

[0002] A digital SLR camera is a single-lens reflex digital camera (Single Lens Reflex). This technology is to install a reflector at a 45° angle in front of the film plane. Above the reflector are ground glass, pentaprism, eyepiece, etc. The pentaprism reflects the real image light multiple times to change the light path and send the image to the eyepiece, so that the image seen in the viewfinder is always the same as that on the film, and the viewfinder range is basically the same as the actual shooting range. The unique design of this prism allows the photographer to directly observe the image through the lens from the viewfinder.

[0003] Among the existing technologies, SLR cameras, mirrorless cameras and film photography technologies have long been mastered by certain foreign companies. There are relatively few companies in China involved in this industry, and there are relatively few designs for SLR lenses and mirrorless lenses.

[0004] Among fixed-focus lenses, they are classified according to the focusing method, and there are swing-out and internal focusing designs;

[0005] The screw-out type is relatively easy to design, but during use, since the structure cannot be completely sealed, dust and water vapor from the outside can easily enter the lens and contaminate the optical lens;

[0006] The internal focus type can completely prevent external dust and water vapor from easily entering the interior of the lens, playing a very good protective role;

[0007] The internal focusing type is classified according to the number of focus groups, and is divided into single-group focusing type and multi-group focusing type;

[0008] In the single-group focusing method, only one lens group moves together during the focusing process, and the lenses within the group are relatively fixed and cannot move; in the multi-group focusing method, at least two lens groups move simultaneously during the focusing process, and the distance between the two lens groups will also change.

[0009] Since the cam barrel processing accuracy of lens manufacturers often does not reach a very high level, coupled with the low processing accuracy of the lenses and low assembly accuracy, the lens production yield is relatively low. Summary of the invention

[0010] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a macro photography optical system. The technical problem to be solved by the present invention is: how to improve the problem of low lens production yield due to low lens processing accuracy and low assembly accuracy, so as to achieve good imaging effect.

[0011] To achieve the above object, the present invention provides the following technical solution: a macro photography optical system, comprising a cemented lens, a focusing lens group, a rear focusing lens group and an image plane mirror in order from the object side to the image side along the optical axis, wherein:

[0012] The cemented lens includes a lens L1 with positive optical power and a lens L2 with positive optical power in sequence from the object side to the image side along the optical axis;

[0013] The focusing group lens includes, from the object side to the image side along the optical axis direction, a lens L3 with negative focal power, a lens L4 with positive focal power, a lens L5 with negative focal power, a lens L6 with positive focal power, an aperture with infinite curvature radius, a lens L7 with negative focal power, a lens L8 with positive focal power, a lens L9 with positive focal power, and a lens L10 with negative focal power;

[0014] The rear focusing lens group includes, from the object side to the image side along the optical axis, a lens L11 with a negative optical power, a lens L12 with a positive optical power, a lens L13 with a positive optical power, and a lens L14 with a negative optical power;

[0015] The image plane mirror is configured as a lens L15 with an infinite radius of curvature and an image plane.

[0016] In a preferred embodiment, the lenses L1-L14 are all configured as glass concave / convex spherical lenses, and the aperture is configured as a variable aperture.

[0017] In a preferred embodiment, the lens comprises a cemented lens, a focusing lens group, a rear focusing lens group and an image plane mirror in order from the object side to the image side along the optical axis, wherein:

[0018] The cemented lens includes a lens L1 with positive optical power and a lens L2 with positive optical power in sequence from the object side to the image side along the optical axis;

[0019] The focusing group lens includes, from the object side to the image side along the optical axis direction, a lens L3 with positive focal power, a lens L4 with positive focal power, a lens L5 with negative focal power, a lens L6 with positive focal power, an aperture with infinite radius of curvature, a lens L7 with negative focal power, a lens L8 with negative focal power, a lens L9 with positive focal power, and a lens L10 with negative focal power;

[0020] The rear focusing lens group includes, from the object side to the image side along the optical axis, a lens L11 with positive focal power, a lens L12 with negative focal power, a lens L13 with positive focal power, and a lens L14 with positive focal power;

[0021] The image plane mirror is configured as a lens L15 with an infinite radius of curvature and an image plane.

[0022] In a preferred embodiment, the lenses L1-L14 are all configured as glass concave / convex spherical lenses, and the aperture is configured as a variable aperture.

[0023] In a preferred embodiment, the optical system includes a front focusing lens, a focusing lens group, a rear focusing lens group and an image plane mirror from the object side to the image side in the optical axis direction, wherein:

[0024] The front focusing lens is set to be a lens L1 with positive optical power;

[0025] The focusing group lens includes, from the object side to the image side along the optical axis direction, a lens L2 with positive focal power, a lens L3 with negative focal power, a lens L4 with positive focal power, a lens L5 with positive focal power, a lens L6 with positive focal power, an aperture with negative focal power, a lens L7 with positive focal power, a lens L8 with positive focal power, a lens L9 with negative focal power, and a lens L10 with positive focal power;

[0026] The rear focusing lens group includes a lens L11 with negative optical power, a lens L12 with positive optical power, and a lens L13 with positive optical power in sequence from the object side to the image side along the optical axis;

[0027] The image plane mirror is configured as a lens L14 with an infinite radius of curvature and an image plane.

[0028] In a preferred embodiment, the lenses L1-L13 are all configured as glass concave / convex spherical lenses, and the aperture is configured as a variable aperture.

[0029] Technical effects and advantages of the present invention:

[0030] The present invention adopts a spherical lens made of all glass material, and places a variable aperture between the focus groups. The variable aperture moves with the focus group, thereby improving and balancing the aberration level at each focus distance. The combined cemented lens has the function of eliminating aberrations and is fixed relative to the imaging surface. When the focus group moves, dust and water vapor are prevented from entering the lens. The last lens of the lens group is set as a convex lens, which plays a role in reducing the incident angle of the main light of each field of view and increasing the back focal length, making it suitable for SLR cameras, micro single cameras and even movie cameras, and achieving good imaging effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the lens of Example 1 of the present invention.

[0032] Figure 2 Schematic diagram of a lens according to Embodiment 2 of the present invention.

[0033] Figure 3 Schematic diagram of the lens of Example 3 of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Embodiment 1:

[0036] The present invention provides Figure 1 A macro photography optical system shown in the figure includes a cemented lens, a focusing lens group, a rear focusing lens group and an image plane mirror in order from the object side to the image side along the optical axis, wherein:

[0037] The cemented lens includes a lens L1 with positive optical power and a lens L2 with positive optical power in sequence from the object side to the image side along the optical axis;

[0038] The focusing group lens includes, from the object side to the image side along the optical axis direction, a lens L3 with negative focal power, a lens L4 with positive focal power, a lens L5 with negative focal power, a lens L6 with positive focal power, an aperture with infinite curvature radius, a lens L7 with negative focal power, a lens L8 with positive focal power, a lens L9 with positive focal power, and a lens L10 with negative focal power;

[0039] The rear focusing lens group includes, from the object side to the image side along the optical axis, a lens L11 with a negative optical power, a lens L12 with a positive optical power, a lens L13 with a positive optical power, and a lens L14 with a negative optical power;

[0040] The image plane mirror is configured as a lens L15 with an infinite radius of curvature and an image plane;

[0041] The specific surface coefficients are shown in the following table: (unit: mm)

[0042]

[0043]

[0044]

[0045] Infinity focus Minimum focus distance M 0 1 EFL 85.061 76.782 S0 Infinity 150.053 S4 52.516 2.000 S19 3.009 53.530

[0046] Wherein: aperture factor (Fno) = 2.8, effective focal length (EFL) = 85mm, magnification M = 0-1;

[0047] -2000 <f1-2<-500

[0048] 20 <f3-10<200

[0049] -900 <f11-14<-200

[0050] 0.1 <f / TTL<0.3

[0051] WL>150

[0052] f1-2 is the composite focal length of lens L1 to lens L2, f3-10 is the composite focal length of lens L3 to lens L10, f11-14 is the composite focal length of lens L11 to lens L14, f is the comprehensive focal length of the entire system, TTL is the distance from the object to the center of the image plane, WL is the distance from the object to the front end of the first lens, and all lenses use glass spherical lenses;

[0053] The variable aperture is located between the focus group (lens L3-lens L10) and moves with the focus group, thereby improving and balancing the aberration level at each focus distance;

[0054] The cemented lens composed of lens L1 and lens L2 has the function of eliminating aberrations to a certain extent, and is fixed relative to the imaging surface; when the focus group moves, it also prevents dust and water vapor from entering the interior of the lens and contaminating the internal optical structure;

[0055] The last lens - lens L14 is a convex lens, which plays the role of reducing the incident angle of the main light in each field of view and increasing the back focal length, making this optical model suitable for SLR cameras, micro single cameras, and even movie cameras.

[0056] Embodiment 2:

[0057] The present invention provides Figure 2 A macro photography optical system shown in the figure includes a cemented lens, a focusing lens group, a rear focusing lens group and an image plane mirror in order from the object side to the image side along the optical axis, wherein:

[0058] The cemented lens includes a lens L1 with positive optical power and a lens L2 with positive optical power in sequence from the object side to the image side along the optical axis;

[0059] The focusing group lens includes, from the object side to the image side along the optical axis direction, a lens L3 with positive focal power, a lens L4 with positive focal power, a lens L5 with negative focal power, a lens L6 with positive focal power, an aperture with infinite radius of curvature, a lens L7 with negative focal power, a lens L8 with negative focal power, a lens L9 with positive focal power, and a lens L10 with negative focal power;

[0060] The rear focusing lens group includes, from the object side to the image side along the optical axis, a lens L11 with positive focal power, a lens L12 with negative focal power, a lens L13 with positive focal power, and a lens L14 with positive focal power;

[0061] The image plane mirror is configured as a lens L15 with an infinite radius of curvature and an image plane;

[0062] The specific surface coefficients are shown in the following table: (unit: mm)

[0063]

[0064]

[0065]

[0066] Infinity focus Minimum focus distance M 0 1 EFL 105.026 65.846 S0 Infinity 153.299 S4 41.080 2.000 S19 2.924 42.006

[0067] Wherein: aperture factor (Fno) = 2.8, effective focal length (EFL) = 105mm, magnification M = 0-1;

[0068] 500 <f1-2<1500

[0069] 20 <f3-10<150

[0070] -500 <f11-14<-50

[0071] 0.1 <f / TTL<0.3

[0072] WL>153

[0073] f1-2 is the composite focal length of lens L1 to lens L2, f3-10 is the composite focal length of lens L3 to lens L10, f11-14 is the composite focal length of lens L11 to lens L14, f is the comprehensive focal length of the entire system, TTL is the distance from the object to the center of the image plane, WL is the distance from the object to the front end of the first lens, and all lenses use glass spherical lenses;

[0074] The variable aperture is located between the focus group (lens L3-lens L10) and moves with the focus group, thereby improving and balancing the aberration level at each focus distance;

[0075] The cemented lens composed of lens L1 and lens L2 has the function of eliminating aberrations to a certain extent, and is fixed relative to the imaging surface; when the focus group moves, it also prevents dust and water vapor from entering the interior of the lens and contaminating the internal optical structure;

[0076] The last lens - lens L14 is a convex lens, which plays the role of reducing the incident angle of the main light in each field of view and increasing the back focal length, making this optical model suitable for SLR cameras, micro single cameras, and even movie cameras.

[0077] Embodiment 3:

[0078] The present invention provides Figure 3 A macro photography optical system shown in the figure comprises a front focusing lens, a focusing lens group, a rear focusing lens group and an image plane mirror in order from the object side to the image side along the optical axis, wherein:

[0079] The front focusing lens is set to be a lens L1 with positive optical power;

[0080] The focusing group lens includes, from the object side to the image side along the optical axis direction, a lens L2 with positive focal power, a lens L3 with negative focal power, a lens L4 with positive focal power, a lens L5 with positive focal power, a lens L6 with positive focal power, an aperture with negative focal power, a lens L7 with positive focal power, a lens L8 with positive focal power, a lens L9 with negative focal power, and a lens L10 with positive focal power;

[0081] The rear focusing lens group includes a lens L11 with negative optical power, a lens L12 with positive optical power, and a lens L13 with positive optical power in sequence from the object side to the image side along the optical axis;

[0082] The image plane mirror is configured as a lens L14 with an infinite radius of curvature and an image plane;

[0083] The specific surface coefficients are shown in the following table: (unit: mm)

[0084]

[0085]

[0086]

[0087]

[0088] Wherein: aperture factor (Fno) = 2.8, effective focal length (EFL) = 150mm, magnification M = 0-1;

[0089] 100 <f1<1000

[0090] 20 <f2-9<150

[0091] -200 <f10-13<-20

[0092] 0.1 <f / TTL<0.3

[0093] WL>207

[0094] f1 is the focal length of lens L1, f2-10 is the composite focal length from lens L2 to lens L10, f10-13 is the composite focal length from lens L10 to lens L13, f is the integrated focal length of the entire system, TTL is the distance from the object to the center of the image plane, WL is the distance from the object to the front end of the first lens, and all lenses use glass spherical lenses;

[0095] The variable aperture is located between the focus group (lens L2-lens L9) and moves with the focus group, thereby improving and balancing the aberration level at each focus distance;

[0096] In addition to eliminating aberrations, lens L1 is fixed relative to the imaging surface. When the focus group moves, it also prevents dust and water vapor from entering the lens and contaminating the internal optical structure.

[0097] The last lens - lens L13 is a convex lens, which plays the role of reducing the incident angle of the main light in each field of view and increasing the back focal length, making this optical model suitable for SLR cameras, micro single cameras, and even movie cameras.

[0098] Finally, a few points should be explained: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, which may refer to mechanical connection or electrical connection, or internal communication between two components, or direct connection. "upper", "lower", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may change;

[0099] Secondly: In the drawings of the embodiments disclosed in the present invention, only the structures related to the embodiments disclosed in the present invention are involved, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0100] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A macro photography optical system, characterized in that: It includes a cemented lens, a focusing lens group, a rear focusing lens group and an image plane mirror from the object side to the image side along the optical axis, wherein: The cemented lens includes a lens L1 with positive optical power and a lens L2 with positive optical power in sequence from the object side to the image side along the optical axis; The focusing group lens includes, from the object side to the image side along the optical axis direction, a lens L3 with negative focal power, a lens L4 with positive focal power, a lens L5 with negative focal power, a lens L6 with positive focal power, an aperture with infinite curvature radius, a lens L7 with negative focal power, a lens L8 with positive focal power, a lens L9 with positive focal power, and a lens L10 with negative focal power; The rear focusing lens group includes, from the object side to the image side along the optical axis, a lens L11 with a negative optical power, a lens L12 with a positive optical power, a lens L13 with a positive optical power, and a lens L14 with a negative optical power; The image plane mirror is configured as a lens L15 with an infinite radius of curvature and an image plane.

2. A macro photography optical system according to claim 1, characterized in that: The lenses L1-L14 are all configured as glass concave / convex spherical lenses, and the aperture is configured as a variable aperture.

3. The macro photography optical system according to claim 1, characterized in that: It includes a cemented lens, a focusing lens group, a rear focusing lens group and an image plane mirror from the object side to the image side along the optical axis, wherein: The cemented lens includes a lens L1 with positive optical power and a lens L2 with positive optical power in sequence from the object side to the image side along the optical axis; The focusing group lens includes, from the object side to the image side along the optical axis direction, a lens L3 with positive focal power, a lens L4 with positive focal power, a lens L5 with negative focal power, a lens L6 with positive focal power, an aperture with infinite radius of curvature, a lens L7 with negative focal power, a lens L8 with negative focal power, a lens L9 with positive focal power, and a lens L10 with negative focal power; The rear focusing lens group includes, from the object side to the image side along the optical axis, a lens L11 with positive focal power, a lens L12 with negative focal power, a lens L13 with positive focal power, and a lens L14 with positive focal power; The image plane mirror is configured as a lens L15 with an infinite radius of curvature and an image plane.

4. A macro photography optical system according to claim 3, characterized in that: The lenses L1-L14 are all configured as glass concave / convex spherical lenses, and the aperture is configured as a variable aperture.

5. The macro photography optical system according to claim 1, characterized in that: It includes a front focusing lens, a focusing lens group, a rear focusing lens group and an image plane mirror from the object side to the image side along the optical axis, wherein: The front focusing lens is set to be a lens L1 with positive optical power; The focusing group lens includes, from the object side to the image side along the optical axis direction, a lens L2 with positive focal power, a lens L3 with negative focal power, a lens L4 with positive focal power, a lens L5 with positive focal power, a lens L6 with positive focal power, an aperture with negative focal power, a lens L7 with positive focal power, a lens L8 with positive focal power, a lens L9 with negative focal power, and a lens L10 with positive focal power; The rear focusing lens group includes a lens L11 with negative optical power, a lens L12 with positive optical power, and a lens L13 with positive optical power in sequence from the object side to the image side along the optical axis; The image plane mirror is configured as a lens L14 with an infinite radius of curvature and an image plane.

6. The macro photography optical system according to claim 5, characterized in that: The lenses L1-L13 are all configured as glass concave / convex spherical lenses, and the aperture is configured as a variable aperture.

Images